Решение:
80 + 80 * 20% = 80 + 80 * $\frac{20}{100}$ = 80 + 8 * 2 = 80 + 16 = 96;
80 + 80 * 30% = 80 + 80 * $\frac{30}{100}$ = 80 + 8 * 3 = 80 + 24 = 104;
80 + 80 * 65% = 80 + 80 * $\frac{65}{100}$ = 80 + $\frac{8 * 13}{2}$ = 80 + 4 * 13 = 80 + 52 = 132;
80 + 80 * 80% = 80 + 80 * $\frac{80}{100}$ = 80 + 8 * 8 = 80 + 64 = 144.
Ответ: 96; 104; 132; 144.

Решение:
60 − 60 * 15% = 60 − 60 * $\frac{15}{100}$ = 60 − $\frac{60 * 3}{20}$ = 60 − 3 * 3 = 60 − 9 = 51;
60 − 60 * 20% = 60 − 60 * $\frac{20}{100}$ = 60 − 6 * 2 = 60 − 12 = 48;
60 − 60 * 25% = 60 − 60 * $\frac{25}{100}$ = 60 − $\frac{60}{4}$ = 60 − 15 = 45;
60 − 60 * 75% = 60 − 60 * $\frac{75}{100}$ = 60 − $\frac{60 * 3}{4}$ = 60 − 15 * 3 = 60 − 45 = 15.
Ответ: 51; 48; 45; 15.